My mag is fighting me

[Peter]

hello guys,
yeah, another magneto topic
i bought a scintilla and wanted to see if it has advance or not...
so..installed it...0,5 mm plug gap, with the cigarette paper i set the advance to about 15°
but it wouldnt start.. advanced a bit... then it started and was running and then died again...
now not possible to start anymore?
is there a trick with these things? the engine should run fire up from 10- 30°, right?

worth to mention is that the engine runs fine with other ignition, so its not carb related

Peter

[TexasTom]

How much gap do the trigger points have?

TxT

[Peter]

hello Tom,
fiddled a bit more today and got it running again...
i could check the advance finally, and i need to modify the mag...
the advance goes up to +- 45° when the rpm's go up..
i set it statically at 15°, so i need to find a way  so it advances max to +- 30°

[Ole]

45°  advance

Then you'd have to start the engine at 15° AFTER TDC...

Or do you get 45 if set to 15 static? If so it's still 30°.

Most "stock" Mags come with 12ish advance.

If it's a race car just lock it, if it's a street car put it to 20-22°.

Ole

[Peter]

Haha Ole, i know
i thought this is a stock one (it came off an industrial engine the seller told me)
maybe my timing light is playing tricks on me ? allthough it works fine with the electronic ignition..
I just revved the engine up to see the advance...No driving with 45° i also didnt rev higher, so advance might have been even more at 7000?

on the mag it says: 0° at 400 and 12° at 1750 i think... so thats why i set it statically at 15 to get around 28 full out...
but it advances further.... I thought it could be due to the engine running faster than 2000 and pushing the advance weights further than they should be?
or is there a stop somewhere that stops the weights? i tried to open it up, but i dont have the correct tools or knowledge about them, so i couldnt take a look at the weights..these things are made to never take apart!!

cheers, Peter

[sam P]

RPM and degrees marked on the magneto are camshaft degrees.
x2 for crankshaft degrees, that makes: 0° at 800rpm, 24° at 3500rpm.
15° initial advance is too much, give it 8° initial, this should give you 32° at 3500rpm. Llisten to your engine when you drive it hard.

[Peter]

thanks Sam!
I ll try it